A CHRONIC knee injury has ended the career of Cowboys workhorse Ben Hannant effective immediately.

Hannant only signed a one-year extension with North Queensland two weeks ago, but a debilitating knee injury has reduced the joint to ‘bone grinding on bone’ and forced him to call time on his 12-year, 245-game NRL career.

The 31-year-old’s autumn years in the game saw him back to his best and playing a key role in the Cowboys breakthrough 2015 premiership, going on to secure a contract for next season after a drawn out negotiation process.

But after six Tests, 12 Queensland Origin caps and stints with the Roosters, Brisbane, Canterbury and the Cowboys, Hannant has faced up to the fact his body was not up to the rigours of another NRL pre-season.

A final assessment from the Cowboys medical staff is required before an official announcement can be made, but it’s understood Hannant is resigned to ending his career as a dual premiership winner (first with Brisbane in 2006 and then North Queensland nine years later) after first debuting in 2005.

The Cowboys are now expected to hit the open market hunting a replacement prop following the departure of both Hannant and fellow big name front-rower James Tamou.

Melbourne’s Jordan McLean had recently been sounded out as an ideal fit for the hole left by Tamou, but the Storm quashed talk of an early release from the final two years of his contract.

With wife Emma and six kids based on the Gold Coast, Hannant recently revealed the full toll his NRL career had taken on his body after another round of off-season surgery on his left knee.

While happy with his form in 2016, his decision to retire has been made to put his young family first.